RKI Instruments GX-82A Owner's manual

INSTRUCTION MANUAL

MODEL GX-82A

PORTABLE THREE GAS DETECTOR

RKI Instruments, Inc.

33248 Central Ave. Union City CA 94587 • Tel: 510-441-5656

Model GX-82A Instruction Manual

062796 RKI Instruments, Inc. Table of Contents

Table of Contents

INTRODUCTION 1

DESCRIPTION 2

COMPONENTS AND CONTROLS 3

Case 3

Control Panel 3

Switches 3

Battery Compartment 4

Interface Port 4

Buzzers and Earphone 5

Carrying Case 5

Sensors 5

Combustible Gas Sensor 5

Oxygen Sensor 6

CO, or H

2

S (toxic gas) Sensor 6

OPERATION 7

Preparation 7

Standard Start-up 7

Normal Operation 9

DISPLAY FUNCTIONS 10

User and Station ID 10

Peak 10

Average 11

Elapsed Time 11

Short-Term Exposure Limit (STL) 11

Time-Weighted Average (TWA) 12

Battery Voltage 12

Date / Time 12

Clear Data Logger 13

Log. Time 13

ALARMS 14

Alarm Indications 14

Resetting Alarms 15

Malfunction Alarm and Emergency Operation 16

Low Battery Alarm 17

CALIBRATION 18

Calibration Supplies and Equipment 18

Demand Zero and Calibration Preparation 18

Calibration Start-up 19

Auto Calibration 20

Combustibles Span 22

Oxygen Zero 23

H

2

S and CO Span 24

Model GX-82A Instruction Manual

Table of Contents Hayward, California (510) 441-5656

MAINTENANCE 25

Batteries 25

Sensor Maintenance 26

Combustibles Sensor 26

O

2

Sensor 27

Toxics Sensors 27

Sensor Replacement 27

CO Filter 28

ACCESSORIES 29

Extender Cable 29

Sample-Drawing Pump 29

Manually-Operated Sample-Drawing Aspirator 30

USER OPTIONS 32

Entering Programming Mode 32

General Programming Hints 32

WARRANTY 37

Model GX-82A Instruction Manual

062796 RKI Instruments, Inc. 1

INTRODUCTION

The RKI Model GX-82A is an advanced gas detection instrument,

incorporating proven detection hardware and microprocessor controls.

The GX-82A is compact, convenient, and offers a full range of

features, including:

• Simultaneous detection of combustible gas, oxygen deﬁciency, and

carbon monoxide or hydrogen sulﬁde (detection for other toxic

gases is optional)

• Dot-matrix liquid crystal display (LCD) for complete, understand-

able information at a glance

• Distinctive audible alarms for dangerous conditions and malfunc-

tions

• Intrinsic safety for Class I, Division I, Groups A, B, C, and D haz-

ardous atmospheres

• Microprocessor control for reliability, ease of use, and advanced

capabilities, including data logging and user-adjustable alarms

• Convenient size, with the full range of well-known GX-82 acces-

sories

WARNING

THE GX-82A IS DESIGNED TO DETECT COMBUSTIBLE

GAS

, OXYGEN DEFICIENCY, AND HYDROGEN SULFIDE OR

CARBON

MONOXIDE, WHICH CAN BE LETHAL. USERS

MUST

FOLLOW THE INSTRUCTIONS AND WARNINGS IN

THIS

MANUAL TO ASSURE PROPER AND SAFE OPERATION

OF

THE INSTRUMENT.

Model GX-82A Instruction Manual

2 Hayward, California (510) 441-5656

DESCRIPTION

The RKI Model GX-82A detects combustible gas (LEL), oxygen

deﬁciency (O

2

), and carbon monoxide (CO) or hydrogen sulﬁde

(H

2

S). See Table 1 for standard detection ranges for these gases. Gas

detection features include distinctive alarms for dangerous gas

concentrations, time-weighted averaging and short term exposure

limit for toxic gases, and logging of detection data.

The GX-82A has a rugged plastic housing, touch-pad control panel,

and a back-lit dot matrix LCD. The included carrying case protects the

instrument and allows hands-free operation for the user.

The GX-82A is easy to adjust and maintain, with user-replaceable

batteries and sensors. The microprocessor control enables the user to

display a comprehensive listing of gas levels detected and other

related data.

Table 1: Standard Detection Ranges

Gas

Detected

Range

Combusti-

ble

0 - 100% LEL (lower

explosive limit)

O

2

0 - 40%

H

2

S 0 - 100 ppm (parts per mil-

lion)

CO 0 - 500 ppm

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062796 RKI Instruments, Inc. 3

COMPONENTS AND CONTROLS

Case

The GX-82A has a durable plastic case. The sensors are housed in a

detachable block at the bottom of the instrument.

Control Panel

The control panel contains the display, alarm lights, and switches that

control the many functions of the GX-82A. The switches are touch-

pads, to reduce the possibility of accidental activation or damage. See

Figure 1.

Switches

1. ON/OFF/ENTER

The ON/OFF/ENTER switch controls power to the instrument.

(Bias power for the electrochemical sensors is not affected by the

power switch.) It also selects input modes to access user-

changeable features.

Figure 1. Contr

ol Panel

% LEL %

PPM

AIR

▲

▼

(SHIFT)

DISPLAY

/(ADJ.)

ON/OFF

/ENTER

OFF - HOLD 5 SEC

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4 Hayward, California (510) 441-5656

2. AIR/▲

The AIR/▲ switch activates the GX-82A’s Demand Zero function,

which automatically adjusts the instrument in fresh-air conditions.

It is also used to scroll through the display and settings modes.

3. (SHIFT)/▼

The (SHIFT)/▼ switch scrolls through the display and settings

modes, and enters instructions into the GX-82A’s microprocessor.

4. DISPLAY/(ADJ)

The DISPLAY/(ADJ) switch activates the display modes, and

enters instructions into the GX-82A’s microprocessor.

5. Alarm LEDs

Three red light-emitting diodes (LEDs) provide visual alarms for

gas concentrations and malfunctions.

Battery Compartment

The GX-82A uses two “C” size cells; alkaline batteries will run the

GX-82A for approximately 10 hours, rechargeable nickel-cadmium

batteries will run for approximately 7 hours. (Rechargeable batteries

can be recharged in the GX-82A with the optional battery charger.)

The GX-82A battery compartment is located on the back of the

instrument. The battery cover has a strap to prevent accidental

opening.

Interface Port

The GX-82A’s built-in data logger records gas concentrations at

programmed intervals. These measurements can be downloaded

through the interface port to a PC-compatible computer for use in data

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062796 RKI Instruments, Inc. 5

analysis programs.

Buzzers and Earphone

An electronic buzzer is mounted at the back of the case, behind a felt

screen. The buzzer sounds for gas alarms and system malfunctions.

A 2.5 mm phone jack at the bottom left rear corner of the case

connects to an earphone, for use in high noise environments, and the

battery charger.

Carrying Case

The carrying case has openings for the diffusion grill, buzzer,

earphone/charger jack, control panel, and Data Logger interface port.

The carrying case includes a belt loop and shoulder straps.

Sensors

The sensors are mounted at the rear of the instrument, in a removable

block. A slotted metal cover protects the sensors, but allows

atmosphere to diffuse inward.

Combustible Gas Sensor

The LEL sensor detects combustible gas and vapors in the atmosphere

with a catalytic platinum element. The reaction of gas with oxygen on

the catalyst causes a change in the resistance of the element, which is

converted by the GX-82A into a reading of gas concentration.

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6 Hayward, California (510) 441-5656

Oxygen Sensor

The O

2

sensor is an electrochemical cell, which reacts to the oxygen

in the atmosphere, producing a current proportional to the oxygen

concentration. This current is converted by the GX-82A into an

oxygen reading.

CO, or H

2

S (toxic gas) Sensor

The toxic gas sensor is an electrochemical cell, which reacts to gas in

the atmosphere, producing a current proportional to the concentration

of gas. The current is converted by the GX-82A into a measurement of

gas concentration. The CO sensor uses a charcoal ﬁlter disk that

covers its opening, to eliminate interference from H

2

S.

To maintain sensitivity and stability, these sensors are kept on a

continuous bias current, even when the instrument power is off.

Batteries with an adequate charge must be installed to provide the bias

current.

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062796 RKI Instruments, Inc. 7

OPERATION

Preparation

Normally the GX-82A requires little preparation before use. To install

the GX-82A Extender Cable, see the ACCESSORIES section.

Standard Start-up

1. Press the ON/OFF/ENTER switch once.

a.This message shows only when the “Lunchbreak” feature is

activated (See USER OPTIONS). Press the AIR/▲ switch to

continue Short Term Exposure Limit (STL) and Time-Weighted

Average readings from the last use of the GX-82A. Press DISP/

(ADJ.) to start new STL and TWA readings

Lunchbreak can accumulate up to 100 hours of STL/TWA read-

ings. If the 100-hour limit is exceeded, this prompt appears:

Press AIR/▲ to clear the memory and start accumulation of

readings.

b.The start-up battery check shows the minimum usable and

actual battery voltage (for example, 3.0V for fresh batteries).

STL TWA RESUME

YES:AIR NO:DISP

CANT RESUME

PUSH AIR: CLEAR

BATTERY MIN. 2.3V

BATTERY NOW 3.0V

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c.This message shows to verify that the data logger circuits are set

properly for accurate data collection according to date and time.

Note

The display illustrations in this manual show only “H2S.” If

your instrument detects CO or another toxic gas, informa-

tion for that gas will appear in the H2S section of the dis-

play.

d.These messages show while the GX-82A checks itself for

proper operation. If a malfunction occurs, the display will alert

the user. (The display shows “HC” [hydrocarbons] for the

%LEL reading.)

d.The normal operating display shows after the “OK” message,

showing fresh-air concentrations for all gases. The GX-82A

sounds a double tone to indicate the instrument is in normal

DATE / TIME

MMM DD YY 00:00

SELF DIAGNOSIS

10 SECONDS TO GO

HC O2 H2S

STANDBY

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062796 RKI Instruments, Inc. 9

operation.

HC O2 H2S

OK

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10 Hayward, California (510) 441-5656

2. Verify Operation

To easily verify correct operation of the GX-82A, breathe out over

the diffusion grill of the instrument. The O2 reading should drop

measurably before returning to normal.

To verify detection of combustibles use a controlled source of

ﬂammable vapor, for example, a bottle of isopropyl alcohol. The

audible alarm will sound, the %LEL will blink, and the HC will

ﬂash on the display.

Caution

Do not use gas from a cigarette lighter to test response to

combustibles. Exposing the sensor to uncontrolled high

concentrations of gas in this manner will reduce

response and sensor life.

WARNING

IF THE GX-82A DOES NOT RESPOND TO THESE VERIFICA-

TIONS

, TAKE IT TO A KNOWN “FRESH-AIR” ENVIRON-

MENT

, THEN FOLLOW THE DEMAND ZERO PROCEDURE

DESCRIBED

IN ADJUSTMENT AND CALIBRATION. REPEAT

THE

VERIFY OPERATION PROCEDURE BEFORE USING THE

GX-82A IN A POTENTIALLY HAZARDOUS LOCATION.

Normal Operation

The GX-82A will continuously monitor the atmosphere, and display

the LEL, O

2

, and toxic gas concentrations present. If the GX-82A is

taken into a low-light environment, the display backlight will

automatically turn on. To use with sample-drawing attachments, insert

the probe into the area to be monitored and wait a few seconds for

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062796 RKI Instruments, Inc. 11

response.

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12 Hayward, California (510) 441-5656

DISPLAY FUNCTIONS

While the GX-82A is in normal operation, press the DISPLAY/(ADJ.)

switch to step through the measurement functions. The display will

hold for 20 seconds before reverting to normal detection, or until

DISPLAY/(ADJ.) is pressed to go to the next screen.

User and Station ID

This screen appears only when the user ID option is activated. (See

USER OPTIONS.) Use this screen to verify user, location, or other

programmed information.

To change User and Station ID:

1. At the User and Station ID screen, press ON/OFF/ENTER.

2. The ﬁrst character (left end) on “U ID” will ﬂash. Press AIR or

SHIFT to scroll through 0 - 9, A - Z to select the desired character.

3. Press ON/OFF/ENTER to enter that value and move to the next

character.

4. Repeat steps 1. and 2. until the desired User and Station IDs are

entered.

Peak

The Peak function shows the highest (lowest for O

2

) concentrations

detected since the GX-82A was turned on. Peak readings (indicated

by “P” at the left side of the display) stay in the instrument’s memory

U ID:0123456789

S ID:ABCDEFGHIJ

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062796 RKI Instruments, Inc. 13

until a higher level is detected, the data logger is cleared, or the unit is

turned off.

Average

The Average function shows the average gas concentrations (indicated

by “A” at the left side of the display) detected since the last time the

GX-82A was turned on or the data logger was cleared.

Elapsed Time

The Elapsed Time function shows the time in minutes since the

memory was cleared or the instrument was turned on. This allows the

user to easily track total time over multiple monitoring sessions.

Short-Term Exposure Limit (STL)

The STL function shows the average reading for toxic gases during

the last 15 minutes.

HC O2 H2S

P45 19.5 10.5

HC O2 H2S

A18 20.8 2.5

TIME (OPERATION)

XXX MINUTES

(STL) H2S

PPM XX.X

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14 Hayward, California (510) 441-5656

Time-Weighted Average (TWA)

The TWA function shows the average reading for toxic gases during

the last 8 hours. If 8 hours has not elapsed since the last time the

STEL/TWA was cleared, the average is still calculated over 8 hours,

with the missing time assigned a 0 value for readings.

Battery Voltage

The Battery Voltage function shows the minimum operating voltage

and present battery voltage.

Note

The GX-82A automatically checks battery voltage during

start-up; if the measurement is below 2.3V, the GX-82A will

not operate.

Date / Time

This function shows the current time and date, for example:

(TWA) H2S

PPM XX.X

BATTERY MIN 2.3V

BATTERY NOW 3.0V

DATE / TIME

JUL 8 95 14:23

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062796 RKI Instruments, Inc. 15

Clear Data Logger

The Clear Data Logger function allows the user to reset the data

logger storage to accept a new set of data. Clearing the Data Logger

also resets the Peak, Average, Time in Operation, STL, TWA, and

Log. Time readings. This function shows three displays. Press AIR/▲

to continue through this function, or DISPLAY/(ADJ.) to skip to the

next function.

Log. Time

The Log. Time function shows the time left on the data collection

program. The duration depends upon the frequency of sampling. Press

DISPLAY/(ADJ.) once more to return to the normal operating display.

ARE YOU SURE ?

YES:AIR NO:DISP

CLEARED

OK

CLEAR DATA LOG.

YES:AIR NO:DISP

LOG. TIME: XXX.0

HOURS REMAINING

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16 Hayward, California (510) 441-5656

ALARMS

Alarm Indications

1. Combustibles (%LEL)

If the combustible gas detected exceeds the ﬁrst level alarm setting

(20% LEL for most applications), a pulsed tone will sound, the

%LEL LED will blink, and the “HC” on the display will ﬂash.

If the combustible gas detected rises above the high alarm setting

(50% LEL for most applications), the alarm tone and LED will be

continuous. The LEL alarm may be turned off and on by the user;

see USER OPTIONS.

2. Oxygen

If the oxygen content of the air drops below the low alarm setting

(usually 19.5%), a pulsed tone will sound, the % LED will blink,

and the “O2” on the display will ﬂash.

If the oxygen content of the air rises above the high alarm setting

(usually 23.5%), the alarm tone and LED will be continuous. The

O

2

alarm may be turned off and on by the user; see USER

OPTIONS.

3. H

2

S or CO

If the H

2

S or CO detected exceeds the alarm setting, a pulsed tone

will sound, the PPM LED above the reading will blink, and “H2S”

or “CO” on the display will ﬂash. The toxic gas alarm may be

turned off and on by the user; see USER OPTIONS.

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062796 RKI Instruments, Inc. 17

5. STEL (toxics only)

If the average toxic gas level detected over the last 15 minutes

exceeds the STL, an alarm will sound and the message “STL” will

show on the display in the ﬁeld for that gas. The STEL alarm may

be turned off and on by the user; see USER OPTIONS.

6. TWA (toxics only)

If the average toxic gas level detected over the last 8 hours exceeds

the TWA, an alarm will sound and the message “TWA” will show

on the display in the ﬁeld for that gas.

7. CLG (toxics only)

If toxic gas detected exceeds the ceiling level, the alarm tone and

LED will be continuous, and the display will alternate between

“CLG” and the name of that gas. The CLG alarm may be turned

off and on by the user; see USER OPTIONS.

8. If the full scale reading is exceeded for any channel, the alarm

tone and LED will be continuous. The display will show “MAX”

in the ﬁeld for that gas.

Resetting Alarms

The GX-82A can be set for latching or self-resetting logic. Latching

alarms can not be reset until the gas concentration falls below the

alarm point. When the condition is corrected, press (SHIFT)/▼ to

reset the alarm. Self-resetting alarms will automatically shut off when

the concentration falls below the alarm point. (See USER OPTIONS.)

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RKI Instruments GX-82A Owner's manual

RKI Instruments GX-82A Owner's manual

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